Principles of Quantum PhysicsExperiments have eroded the ideas of point like particles having arbitrarily any amount of energy, of particles having a precise location in space at every given moment, of precise velocities and momenta. It is clear that Classical laws will not work even as an approximation at atomic levels.
We have come to beleive in the dual nature of matter, quantization of energy and uncertainty principle.
So, we need a mathematical model for the new theory. A model, which will help us describe nature and its laws. It will help us in analyzing physical situations. The model will need to be consistent with the experimental results. It will have to be consistent with the dual nature of matter, quatization of energy and the uncertainty principle.